In general I love the Recipe Calculator, but there are a few things that are frustrating:
1. The grains are not in a very logical order. At the beginning of the long popup list, it's pretty good for the base grains, but once specialty grains start, it seems really really messy. How about grouping the grains by country of origin? It's kind of strange that German malts are spread all over the place. Also, when a new grain is added, it's always at the end of the list instead of being sorted by type -- not very user friendly.
2. We need more hops! Right now there are slots for five hop additions (maybe six), I think, plus dry hops. But, many brewers like to use a blend of hops, which each has to be entered separately -- and for that, six isn't enough! Double it at least, please please pretty please?!?!? Also, like the grains, new hops aren't sorted into the list alphabetically, but are all tacked on to the end of the list. Why?
3. How about a cookie that remembers whether I use metric or US weights and volumes? As it is now, it's always set to US measurements and I have to manually change it.

Overall I'm very happy with BeerTools' Recipe Calculator, but it could be much better with these simple changes.

As a long time calculator user, I admit to being perplexed by the slowly growing list of "other" grains that is found at the bottom of the grain list. Integrating these grains would be OK. But I disagree with sorting the grains out by country. Right now, the general structure of the grain list seems to be by the Lovibond rating (aka "darkness") of the malt. I think this makes perfect sense as when I build a recipe I start with a base pale malt, then slowly progress down the list adding more complex grains as desired. If you think the grain list is complicated now, I think ordering the grains by country would add even more complexity. For me, and I am sure I am not alone, I don't necessarily have a choice of what country I get my grains from, but that suits me fine as I love using the readily available Gambrinus malt made right here in Canada. So when I make a recipe here at Beertools, I am using a "proxy" grain anyway b/c Gambrinus isn't listed, and therefore the country of the grain is irrelevant. What matters is the character and colour the grain will add to the beer.

cj in j is onto something with the hop additions. I would really, really, really like to see more hop additions available in the calculator. My favorite hop schedule is rather elaborate and the calculator just doesn't have the room that I need. Also, last time I checked I couldn't use 0 as a boil length. Furthermore, if I make a recipe available to the library, then later decide to include dry hops- the dry hops won't show up on the recipe in the library. So please, pretty please with a keg of beer on top, add more hop additions.

I forgot about the 0 for boil length -- it's annoying to have to type in 0.00001 every time I want to add hops at the end of the boil

I see your point on the grains, but as it is right now the list really is too long -- something can be done to make it easier to find your specific grains. Maybe some separator lines? So, it'll list pale 2-row grains, then have a separator (such as ------------), then Vienna, separator, Munich, etc. It's not all that bad now, and it's not something that will make me stop using BeerTools, but it can be made better, I think.

As the list of ingredients grows it is becoming a bit unwieldy. I like the idea of using separators to group grain types, and within the separators the list could be alphabetical. Not sure how to implement the idea given the current DB scheme but I am sure it is possible.

The maximum quantity of grains, hops, etc. for each recipe will be lifted with the next release of the tools. The database is being redesigned and the new structure will allow for a much more flexible recipe storage system.